As is known in a folder of a printing press, a web of sheet material after being printed thereon can be slit lengthwise into ribbons which are associated or interleaved before being folded, cut, and delivered as signatures. An arrangement of compensator rollers either lengthens or shortens the travel distance of the web of sheet material. The compensator rollers control the lengthwise location of the web of sheet material for accurate association of its ribbons to thereby assure uniform head and tail margins and accurate cut-off.
An arrangement of anglebars associates the ribbons one on top of the other before they are folded, cut, and delivered as signatures. Anglebars are hard smooth metal members around which a web of sheet material slides. The anglebars change the direction of travel of the web of sheet material and can be adjusted angularly as well as lengthwise of the direction of web travel. When an anglebar is adjusted lengthwise of the direction of web travel, the anglebar acts like a compensator roller to lengthen and shorten the travel distance of a web of sheet material.
The use of an electric motor for adjusting an anglebar and/or a compensator roller in a folder of a printing press is well known. The known adjustment of the anglebar and/or the compensator roller is relatively slow and at a constant rate at all operating speeds of the printing press. If the adjustment is made at a fast rate, a break in the web of sheet material may occur under certain circumstances.